6645242021636 has 24 divisors (see below), whose sum is σ = 12316132860696. Its totient is φ = 3126438673920.

The previous prime is 6645242021609. The next prime is 6645242021651. The reversal of 6645242021636 is 6361202425466.

It can be written as a sum of positive squares in 4 ways, for example, as 5913378881536 + 731863140100 = 2431744^2 + 855490^2 .

It is a super-2 number, since 2×6645242021636² (a number of 26 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11177531 + ... + 11757026.

It is an arithmetic number, because the mean of its divisors is an integer number (513172202529).

Almost surely, 2^{6645242021636} is an apocalyptic number.

It is an amenable number.

6645242021636 is a deficient number, since it is larger than the sum of its proper divisors (5670890839060).

6645242021636 is a wasteful number, since it uses less digits than its factorization.

6645242021636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22938839 (or 22938837 counting only the distinct ones).

The product of its (nonzero) digits is 2488320, while the sum is 47.

The spelling of 6645242021636 in words is "six trillion, six hundred forty-five billion, two hundred forty-two million, twenty-one thousand, six hundred thirty-six".